(function () {
  class CSS2DObject extends THREE.Object3D {
    constructor(element = document.createElement("div")) {
      super();

      this.isCSS2DObject = true;

      this.element = element;

      this.element.style.position = "absolute";
      this.element.style.userSelect = "none";

      this.element.setAttribute("draggable", false);

      this.addEventListener("removed", function () {
        this.traverse(function (object) {
          if (object.element instanceof Element && object.element.parentNode !== null) {
            object.element.parentNode.removeChild(object.element);
          }
        });
      });
    }

    copy(source, recursive) {
      super.copy(source, recursive);

      this.element = source.element.cloneNode(true);

      return this;
    }
  }

  //

  const _vector = new THREE.Vector3();
  const _viewMatrix = new THREE.Matrix4();
  const _viewProjectionMatrix = new THREE.Matrix4();
  const _a = new THREE.Vector3();
  const _b = new THREE.Vector3();

  class CSS2DRenderer {
    constructor(parameters = {}) {
      const _this = this;

      let _width, _height;
      let _widthHalf, _heightHalf;

      const cache = {
        objects: new WeakMap(),
      };

      const domElement = parameters.element !== undefined ? parameters.element : document.createElement("div");

      domElement.style.overflow = "hidden";

      this.domElement = domElement;

      this.getSize = function () {
        return {
          width: _width,
          height: _height,
        };
      };

      this.render = function (scene, camera) {
        if (scene.matrixWorldAutoUpdate === true) scene.updateMatrixWorld();
        if (camera.parent === null && camera.matrixWorldAutoUpdate === true) camera.updateMatrixWorld();

        _viewMatrix.copy(camera.matrixWorldInverse);
        _viewProjectionMatrix.multiplyMatrices(camera.projectionMatrix, _viewMatrix);

        renderObject(scene, scene, camera);
        zOrder(scene);
      };

      this.setSize = function (width, height) {
        _width = width;
        _height = height;

        _widthHalf = _width / 2;
        _heightHalf = _height / 2;

        domElement.style.width = width + "px";
        domElement.style.height = height + "px";
      };

      function renderObject(object, scene, camera) {
        if (object.isCSS2DObject) {
          _vector.setFromMatrixPosition(object.matrixWorld);
          _vector.applyMatrix4(_viewProjectionMatrix);

          const visible =
            object.visible === true && _vector.z >= -1 && _vector.z <= 1 && object.layers.test(camera.layers) === true;
          object.element.style.display = visible === true ? "" : "none";

          if (visible === true) {
            object.onBeforeRender(_this, scene, camera);

            const element = object.element;

            element.style.transform =
              "translate(-50%,-50%) translate(" +
              (_vector.x * _widthHalf + _widthHalf) +
              "px," +
              (-_vector.y * _heightHalf + _heightHalf) +
              "px)";

            if (element.parentNode !== domElement) {
              domElement.appendChild(element);
            }

            object.onAfterRender(_this, scene, camera);
          }

          const objectData = {
            distanceToCameraSquared: getDistanceToSquared(camera, object),
          };

          cache.objects.set(object, objectData);
        }

        for (let i = 0, l = object.children.length; i < l; i++) {
          renderObject(object.children[i], scene, camera);
        }
      }

      function getDistanceToSquared(object1, object2) {
        _a.setFromMatrixPosition(object1.matrixWorld);
        _b.setFromMatrixPosition(object2.matrixWorld);

        return _a.distanceToSquared(_b);
      }

      function filterAndFlatten(scene) {
        const result = [];

        scene.traverse(function (object) {
          if (object.isCSS2DObject) result.push(object);
        });

        return result;
      }

      function zOrder(scene) {
        const sorted = filterAndFlatten(scene).sort(function (a, b) {
          if (a.renderOrder !== b.renderOrder) {
            return b.renderOrder - a.renderOrder;
          }

          const distanceA = cache.objects.get(a).distanceToCameraSquared;
          const distanceB = cache.objects.get(b).distanceToCameraSquared;

          return distanceA - distanceB;
        });

        const zMax = sorted.length;

        for (let i = 0, l = sorted.length; i < l; i++) {
          sorted[i].element.style.zIndex = zMax - i;
        }
      }
    }
  }

  THREE.CSS2DRenderer = CSS2DRenderer;
  THREE.CSS2DObject = CSS2DObject;
})();
